1. Field of the Invention
The present invention relates to an electronic endoscope apparatus and an electronic endoscope system, and particularly, to a management technique when an abnormality occurs in a distal end portion of the electronic endoscope in which an imaging device having a solid-state imaging element is built.
2. Description of the Related Art
Electronic endoscope systems used in the medical field or the like are constituted by an electronic endoscope (scope) in which an imaging device including a solid-state imaging element is provided at a distal end portion of an insertion part to be inserted into a subject to be examined, and a processor device that controls the operation of the imaging device, and performs various kinds of signal processing on imaging signals output from the imaging device to display an endoscope image on a monitor (display device).
Inside the distal end of the endoscope insertion part, temperature is apt to rise due to heat generation of the solid-state imaging element, heat generation caused by the loss of the light intensity of a light guide, or the like. If the internal temperature of the endoscope insertion part rises, the noise of the image signals increases and the image quality deteriorates. Additionally, due to a failure of a circuit in the distal end portion etc., overcurrent may flow and heat may be generated. Moreover, if the image signals from the distal end portion are no longer normally sent to the processor device, it is determined to be a dark image, and a control is made in a direction in which an iris (diaphragm mechanism) of a light source device is automatically opened such that the exposure quantity that is required is obtained. If a maximum quantity of light continues being emitted with the iris opened, the distal end portion further generates heat.
Since heat damage may be caused in a human body tissue if the temperature of the endoscope distal end portion reaches a high temperature, it is desired to maintain the temperature of the distal end portion below a certain fixed temperature.
JP1995-194531A (JP-H07-194531) suggests an electronic endoscope apparatus in which temperature detection means is arranged near a solid-state imaging element provided at the distal end of a scope, and when a temperature rise near the solid-state imaging element is detected due to generation of an overcurrent, the control of attenuating or cutting off supply of a driving signal to the solid-state imaging element or waveform shaping means is performed.
Additionally, a capsule endoscope disclosed in JP2004-298241A includes temperature detection means that detects internal temperature, and power source control means that performs the control of stopping supply of power to an internal electric circuit in a case where the internal temperature exceeds a predetermined value.